1. Field of the Invention
The present invention relates to novel prostaglandin (hereinafter referred to as PG) derivatives, and more particularly relates to novel PG derivatives having an excellent lowering action of intraocular pressure and improving actions of renal diseases, ischemic heart diseases and heart failure, and their use as medicines.
2. Prior Art
Since PGs and derivatives thereof exhibit various important physiological actions in a trace amount, investigations have been made of the synthesis and biological activity of natural PGs and a large number of PG derivatives with the intention of use as medicines. Results of these investigations are reported in many publications, for example, Japanese Patent Kokai No. 52-100446, WO 89/00559 and WO 94/02457. The physiological actions of PGs and derivatives thereof include a vasodilating action, an anti-inflammatory action, an inhibiting action of blood platelet aggregation, a uterine muscle contraction action, an intestinal contraction action and a lowering action of intraocular pressure.
As a result of various researches, the present inventors have found novel PG derivatives having a potent lowering action of intraocular pressure with no or less side effects such as transient ocular hypertension, lacrimation, lid closure or iridal hyperemia, as compared with the prior art compounds, as well as potent improving actions of renal diseases, ischemic heart diseases and heart failure, and thereby the present invention has been accomplished.